Method of rolling staybolt iron



March 13, 1928.

s. H. MANSFIELD METHOD OF ROLLING STAYBOLT IRON Filed Nov. 25, 1925WITNESSES .nated, I show in Patented Mar. 13, 1928.

UNITED STATES PATENT OFFICE.

METHOD OF ROLLING STAYBOL'I. IRON.

Application filed November 215, 1925. Serial No. {1,364.

This invention relates to new principles introduced to the rolling,hammering, pressing, or otherwise sha ing of hollow-staybolt iron orsteel bars an has for one of its objects the working or rollin of ahollow bar froman original hollow pi e; another object being to producesuch a bar substantially seamless, still another to materially increasethe tonnage production from a given amount of fuel and labor and hencereduce the cost per pound.

Referrin to the accompanyin drawings, in which similar arts are simiarly desigigure 1 a cross-sectional view of a hollow ile of sectionaliron bars arranged substantlally in the formation of a tube; in Figure 2a steel mandrel designed to be used by insertion into the hollow pile tocontrol the size and contour of the hole thereof; in Figure 3 anillustration of the manner in which the hollow pile is entered into therolls of a rolling mill and of the manner of inserting the said mandrel;in Figure 4 a longitudinal cross-section of an iron container or tubecontaining a refractory core; Figure 5 a-hollow billet evolved fr am thesaid hollow pile, having-the core of Figure 4 inserted therein;.and inFigure 6 a finished hollow st-aybolt bar.

Proceedin to explain the invention in more exact etail, in theconstruction of the hollow pile of Figure 1 I employ, preferably, foursectional bars curved in such a manner that two of them butted againsteach other form a tubular shape and constitute the inner layer 2 of thehollow pile; after which a second or outer layer 1 is provided byenveloping the said inner layer 2 with similarly curved sectional bars.The hollow pile thus formed is charged into a heating furnace andbrought to a welding heat, when it is removed from the furnace androlled throughreducing rolls of a rolling-mill. Such rolls areillustrated in cross-sectional views 13 of Fig. 3, with collars 14. The0 ration is offected b setting the heated ho low-pile u on a suitab ebed as indicated by dotted out ine 14, at which juncture an operativeinserts mandrel 4 into hole 3 to an extent that mandrel-tip 5 reaches alocation'within the pile exactly at a line centrally between the axes ofrolls 13, whereu on another operative entore the pile into t e saidr0115 13, resulting in reduction of its cross-sectional diameter asindicated at 20, while the hole 3 is correspondingly reduced 8 to thediameter of mandrel-tip 5. By provision of a fixed stop upon mandrel-bedl8 and a shoulder-plate 6 on mandrel 4, the'latter is prevented fromaccompanying the pile through the rolls, the rolls, in eli'ect, drawingthe pile off the mandrel. Handle 7 is provided on the mandrel 4 forgrasping by the operative. In Figure 3 is shown a partially cut-outsection to clearly illustrate the longitudinal cross-section of saidpile and the generous clearance space 3 between the mandrel 4 and innerlayer 2 of pile, and which facilitates the entry of the mandrel 4. I maygive the pile additional assages through the rolls over mandrels, eacnumber of such operations is governed by the outside and insidediameters which are desired in the finished bar. After the passages overmandrels, when the pile is thoroughly welded into an integral mass ofiron, it has become an evolved hollow billet as shown at 15 of Fig. 5,into the hollow of which is inserted a core-bar of which a longitudinalcross-section is shown in Fig. 4,

consisting of a tubular container 9 holding a refractory 10, plugged 11at the ends with ed es of container 9 bent over as at 12 to ho dsecurely the plugs 11. Again in Fig. 5 I show a partially cut-outsection of billet 15 to illustrate the disposition of core-bar 9 withinsaid billet 15, which thereupon is rapidly rolled down throu h thesuccessive passes of ordinary rolling-mill. rolls to the desireddiameter of the finished bar 16 of Fig. 6. In these reducing operationsthe core 10 is reduced in cross-section in proportion to the wall of thebillet, evolving into a finished bar of relatively thick wall and smallcore 17, which latter may be extracted in any desired manner, such asdrilling,ream1ng, or water or air pressure.

It is obvious that substitutes for the hollow pile may be used, such asdrilled, pierced or forged masses of iron, and yet remaln within thescope of my inventlon embodying the combinatlon of the principles of themandrels and the core.

'It is further obvious that the core is not restricted to thecombination of a core within a container, as any core substancepossessing an adequate heat-resistmg property and reasonably rigid formfor convenient insertion into the hole of the pil e or billet, would"equall carry out the spmt of my invention. or must it be necessarlly aresuccessively smaller in diameter. The

fractory, since if a cold container be used,

and kept out of the furnace until the pile is drawn therefrom, it wouldbe practicable to employ copper or any other metal or substance offairly high heat-resisting property within the core container; or la'ain, such copper bar may be used unencased, by squirting a stream ofcold water through the hole of the )ile or billet to chill or materiallyreduce the temperature of the immedate inner wall to such an extent aswill not melt the copper, which, retaining its solidity, would occupyits proportion of the crosssectional area in the successive operationsof reduction. In the event of using such metallic core, I wouldpreferably extract it from the finished bar by heat, as in an electricfurnace, to a degree that the copper would melt and flow out, without,however, reachin the critical point of heat of the iron itsel.

It is further obvious that various core refractories can be used, suchas silica sand, mica, fireclay, carbon, and the various products ofelectric or other high-temperature furnaces, such as earborundum,aloxite, siloxicon. calcined magnesite, et

My invention embraces the principle of exposing the unincumbered pile tothe furnace heat, without core or anything what ever inside; thereby theentire inner surface, along with the outer surface, is exposed directlyto the heat, which in effect saves practically 50% of the fuel requiredto heat a given tonnage of iron, hence achieving a wholly new conditionof econ- It is obvious that various substitute core materials might beused by this method, such as hardwood, sawdust, etc., since, while suchmaterials are combustible, yet the core-container 9 is ke t from theheated iron until inserted into hillet 15, thereby acting as a shieldagainst heat reactions of the core.

It is also obvious that ice might be employed as a core, since the soleobject of the core is but to momentarily preserve a relative rigidityand resistance of core-container 9 to the compressive action of the rollpasses.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. The method of making hollow staybolts which consists in assemblingmetal pieces to form a hollow pile, heating said pile, welding saidpieces together and re ducing the cross sectional diameter of said pilein successive sta es, controlling the diameter of hole in tie pile withmandrels during the first stages of reduction and controlling thediameter of hole by a core in the last stages of said reduction, saidcore bein inserted in said pile while said pile is still hot. I

2. The method of making hollow staybolts which consists in assemb ingmetal pieces to form a hollow pile, heating said pile, welding saidpieces together and reducing the cross sectional diameter of said pilein successive stages. controlling the inner diameter of said pile in thefirst stages of reduction with mandrels and controlling the innerdiameter in the last stages of reduction by a core, said core beinginserted in said pile after said pile has been heated.

GEORGE HENRY MANSFIELD.

